[hyde]

I was listening to XM Radio I thought it was reception problem when bass would sometimes go out, but today it went out completely in all sources/inputs, adjusting Bass in EQ makes no difference.

I have zero bass.

Does anyone know if the bass is routed exclusively to subwoofers in the Harman Kardon sound package so maybe I can check something before taking it to dealer? Has anyone heard of this happening? Maybe fuse went out?

[TurtleBoy]

First try rebooting iDrive to see if that brings it back.

[Auricom]

+1 on reboot iDrive first.

Then

For vehicles produced: March 1st to November 23rd 2020

There is also a SIB on bass loss on vehicles equipped with:

688 Harman Kardon Surround Sound System and: 6U2 BMW Live Cockpit Plus Or 6U3 BMW Live Cockpit Professional


SPORADIC FAILURE OR CRACKING NOISE IN BASS SPEAKERS
B65 01 21 [SI] February 2021

Situation
No Bass or a cracking noise can be heard from the bass speakers.

Cause
Fault in the Top HiFi system amplifier control unit.

Model
F44 (2 Series Gran Coupe)
F90 (M5 Sedan)
F91 (M8 Convertible)
F92 (M8 Coupe)
F93 (M8 Gran Coupe)
F95 (X5 M Sports Activity Vehicle (SAV))
F96 (X6 M Sports Activity Coupe (SAC))
F97 (X3 M SAV)
F98 (X4 M SAC)
G01 (X3 SAV)
G02 (X4 SAC)
G05 (X5 SAV)
G06 (X6 SAC)
G07 (X7 SAV)
G12 (7 Series Sedan)
G14 (8 Series Convertible)
G15 (8 Series Coupe)
G16 (8 Series Gran Coupe)
G20 (3 Series Sedan)
G22 (4 Series Coupe)
G29 (Z4 Roadster)
G30 (5 Series Sedan)
G32 (640i xDrive Gran Turismo)

Vehicles produced: March 1st to November 23rd 2020

Vehicles equipped with option code:

688 Harman Kardon Surround Sound System
And:
6U2 BMW Live Cockpit Plus Or 6U3 BMW Live Cockpit Professional

Correction
Replace the Top HiFi system amplifier.

Procedure
1) Perform diagnosis with the latest version of ISTA, working through test modules, if needed.
2) Is the following fault present in the RAM01 control unit : B7F480 – booster, no connection.
YES: Replace the Top HiFi system amplifier
NO: Further diagnosis with ISTA is needed

[finn123]

Had this problem on my MY21. Rebooting idrive never helped. What helped was closing the car for ~5 minutes and opening it again.

However, the final solution was to change the AMP (as the dealer said). Software update to 03/2021 didn’t help, so insist on changing the amp to avoid useless visits to your dealer.

Since the amp was changed (on 7th of June), I haven’t had any problems with bass.

[iceRN09]

My M340i Has the crackling noise that comes and goes. Someday its not there. But it will just pop or crack randomly..

[hyde]

Thanks for the suggestions, I'll reboot to see if it forces a fix, but when I started up this morning I had bass but it sounded weak, it really doesn't sound like there is full bass, either speakers are missing it, or subwoofer is not working.

It's a hassle to take her in, and wait for them to replace the amp, generally everytime they fix something, there is some other issues so I have been avoiding taking my cars to dealers unless absolutely necessary. They said they fixed the camera issue last time, but now the front camera image is overblown on 3D view (ok on front view).

[sygazelle]

Maybe Meghan Trainor can find it for you!

Seriously, I hope you get it sorted out.

[solomonshv]

rebooting idrive will do nothing. this is a defect that BMW won't publicly acknowledge. my 2021 X6 has this issue. come and goes sporadically. ironically, the 2021 X5 i got as a loner while they "fix" my sound system has the same problem. Bass comes and goes whenever it feels like it. sometimes for 1-2 seconds at a time, sometimes for an hour.

i also personally saw this issue on several X7s.

[mitch57]

Take it to the dealer and have them order a new amp. There's an SIB on this issue. https://static.nhtsa.gov/odi/tsbs/20...88953-9999.pdf

[-Vanguard-]

Yep, take to dealer to change out a module in your trunk. Known issue.

[biterror]

Visited my dealer and they told me no no no, first we will update the software (although they just updated it last month), then we wait to see if the problem goes away, then we run diagnostics and then we may or may not order a new amplifier. And if we do, it will probably take 5-6 months to get one.

The first change for updating the software is in 10 days..

Great.

[hyde]

I just got a OTA software update today, haven't applied it yet, but somehow bass is working and has been working for 3 days without cutting out. I would really love to see the cause of this, if it was overheating, shouldn't it be consistent? I will update software and try to document bass loss before taking her in. Seems like no one confirmed solution to this problem.

[eneudecker]

Has anyone had their dealer first recommend replacing the subwoofer for this issue? Our issue sounds the same as everyone else - random loss of the bass / low end of the sound. Comes and goes, maybe 1 - 2x per month. Everything I've read states this is a problem with the AMP, not the sub. This is extremely frustrating!

[biterror]

Originally Posted by eneudecker

Has anyone had their dealer first recommend replacing the subwoofer for this issue? Our issue sounds the same as everyone else - random loss of the bass / low end of the sound. Comes and goes, maybe 1 - 2x per month. Everything I've read states this is a problem with the AMP, not the sub. This is extremely frustrating!

Which software version does your car have? A software upgrade (07/2021.50) fixed the problem for me (at least it seems so).

[motex]

Today I noticed a lost of all Bass on my HK System, anyone here with an update about any new findings where the problem is located, or DIY solutions?

I will leave the car closed for a few hours in order to let all systems to be restored, and and will check later to see if the problem persists before I take it to my dealer.

[hyde]

No solution that I know of, it's very frustrating but it hasn't been happening much lately, I don't know what causes it either. I wouldn't be surprised if it's working fine when you take her to dealer.

[motex]

Problem fixed, after one hour, i started the car and everything was working as it should, probably just a computer temporary bug.

[biterror]

Originally Posted by hyde

No solution that I know of, it's very frustrating but it hasn't been happening much lately, I don't know what causes it either. I wouldn't be surprised if it's working fine when you take her to dealer.

They updated the software in my car because of this problem and I haven't had the problem in about 1.5 years now.

[Heavyd]

Dealer replaced something. I think amplifier or woofer and since than no issues anymore.
It’s a documented issue with BMW.

[Sriki]

Originally Posted by finn123

Had this problem on my MY21. Rebooting idrive never helped. What helped was closing the car for ~5 minutes and opening it again.

However, the final solution was to change the AMP (as the dealer said). Software update to 03/2021 didn’t help, so insist on changing the amp to avoid useless visits to your dealer.

Since the amp was changed (on 7th of June), I haven’t had any problems with bass.

Hello! Has this helped fix the issue?
I recently purchased a used x5 2021 and have the same issue.
Also, is amp part of new car warranty?

[R3v1v3]

Originally Posted by Sriki

Hello! Has this helped fix the issue?
I recently purchased a used x5 2021 and have the same issue.
Also, is amp part of new car warranty?

Yes it should be still under warranty. Call your dealer and get it replaced.

[biterror]

On my 45e the problem went away after a software update performed by the dealer. I was telling them I wanted the new amplifier, but they said they had to try the sw update first. I didn't believe it would help but I was wrong..